Air lift



Jan. 8, 1929. 1,698,127

G. c. ENGSTRAND AIR LIFT Filed Aug. 5, 192 s INVENTOR:

Patented Jan. #8, 1929.

UNITED s'mrss a trace.

GUNNAR C. ENGSTRAND, 0F BROOKLYN, NEW YORK, ASSIGNOR; BY MESN'E ASSIGN-MENTS, TO SALVAGE PROCESS CORPORATION, OF NEW YORK, N. Y., A CORPORA-TION OF NEW YORK.

AIR LIFT. I

Application'filed August 5, 1926. Serial No. 127,342.

My invention has for its object to provide an apparatus and a methodwhereby viscous material can be pumped at acommercial pumping ratewithout interruption of service.

It has for its object to furnish an air lift emptying out in a suctiontank from which tank the viscous material is pumped by a transfer pump.v

It has also for its object to provide an air lift supplied with anintake nozzle the-submergence of which can be varied as the nature forthe material to be pumped may require;

I have discovered that at a certainsubmergence a certain material can bepumped at a commercial rate'of pumping. I have also discovered that whena commercial nozzle.

-By increasing or decreasing the depth to which the intake nozzle issubmerged a'point is found at which the air admittance is so sealed thata sufficiently high-air inrush velocity will develop so as to break upthe viscous material. I

My invention also provides means Whereby the vacuum in the'air lift canbe temporarily increased above the vacuum existing in the suction' tank.

In the drawing ratus.

Figure 2 is an end elevation of thesame. Referring to the drawing inwhich like reference characters designate corresponding parts, 1represents the air lift whlch terminates in the cylindrical fitting 2fromv which fitting the air is, exhausted by the vacuum pump 4 throughthe line 3'.

The fitting 2 has the discharge leg 5 appended. The discharge. 5 isprovided with the check valve 6 and is at its end connected to tank 9. I

The tank 9 is also connected withthe vacuum line 3 through the by passline 7 which is provided with the pressure regulating valve'8.

The tank; 9 is also provided mospheric relief valve 10.

A strainer 11 extends longitudinally through the tank 9 and the materialpumped has to pass through the same before it falls with the atentirelyclog the line.

Figure 1 shows a plan view of the appato the bottom of the tank fromwhich it is removed by the transfer pump 13 through the pipe line 12.The pump 13 is connected to the discharge pressure line 14, throughwhich line the material pumped is finally disposed of. I

The intake end 15 is supplied with the internal reducing sleeve 16, andthe pipe 17 forms a conductor through which atmospheric air is admittedto the formed annular space around said internal sleeve. A float 18regulates valve 19 which is provided in the steam line to the pump.

The operation is as follows :The vacuum pump 4 is started and thesuction end is insorted into the material to be pumped. By

means of lowering or raising the intake end a point will be found atwhich the bottom of the annular spacesurrounding the internal reducingsleeve is so sealed bythe material which is sucked up into thetransmission line that the 'air in passing out from'the said annularspace 'will attain a velocity sufficiently high to break up the viscousmaterial-which passes into the transmission line.

A point is soon reached where the sucked up spray will interfere withthe air current in the air lift line 1, whereupon the sucked up viscous.material will adhere to the inside of the air lift and in accumulatingwill soon It is to be noted that the vacuum in the air lift is the sameas that existing in the tank 9 as long as the by pass valve 8 is open.This valve however is so; regulated and connected that. it willautomatically close when the vacterial clogs thea-ir lift the vacuumwill rapidly increase in the transmission line thus causing the cloggingmaterialslug to travel through the line at a great velocity. It is to benoted that the valve 8 will not close before, the vacuum in the air liftreaches a certain point and it is therefore of the greatest importanceto keep the tank 9 nearly full during the pumping so that the air spaceleft in the tank will be small. By so doing it is possible toconsiderably reduce the capacity of the vacuum pump which intermittentlymust exhaust the air space in the suction tank in addition to the airlift until the vacuum necessary for the closing of the valve 8 isreached. I

The float, 18 which is housed in the tank is connected to the regulatingvalve 19 .in such a manner that the valve will. open or close'as theliquid level in the tank rises or recedes" and the pump will speed up orslow down accordingly. The liquid level in the tank is thus keptconstant during'the pumping and the regulating float is so arranged thatthe air space in the tank is as small as possible. The time the vacuumpump requires to exhaust the air space decreases with its volume and asthe pump must repeatedly exhaust this space in addition to the vacuumline whenever a sealing slug is built up in the line as previouslydescribed, a considerable reduction in the size of the vacuum pump willbe attained when the air space is small.

The employment of a pressure regulating valve operated from the vacuumline makes it imperative to use a small air space with a small capacityvacuum pump. Were acheck valve instead of a pressure regulating valveused the size of the air space would be immaterial as the vacuum in thetank would always be equal to the maximum vacuum in the vacuum line andno repeated exhausting of the space would occur.

It is to be pointed out that if a slug is allower to form at the intakeend so that the viscous material is not thoroughly mixed with air theslug will adhere to the transmission line most tenaciouslyand itsprogress will be so impeded that the pumping rate will become too slowfor commercial purposes. By admitting air so that the viscous materialis initially blown in a spray when entering the line the viscosity ofthe sealing slug is materially reduced and the pumping rate becomescommercial. A 4 hose will pump only five barrels an hour when the air isnot allowed to mix with the material, but

it will pump more than fifty barrels an liourv when the viscous materialis initially blown into a spray. a

I do not wish to myself to the specificdetails of construction as it ismanifest that variations and modifications may be made in the adaptationof the device to various conditions without departing from the spiritand scope of my invention.

I claim i In a pumping apparatus a low suction tank, anair liftdischarging in said tank, a by pass connecting the top of the suctiontank to the air lift and a pressure regulating valve which will closethe by pass when a predetermined vacuum is reached i the air lift and inthe low suction tank.

GUNNAR O. ENGSTRAND.

be understood as limiting

